This invention relates to a device for damping a rotor engaging with a part such as the lid of the cassette holder in a cassette tape recorder or deck so as to thereby damp the movement of such a part.
Generally, the mechanism for opening and closing the lid for the cassette holder in a cassette tape recorder is so designed that a push given to an eject button causes a spring to snap open the lid. When the lid is opened, the energizing force of the spring acts wholly upon the lid and causes the lid to open abruptly and, after the lid has reached the limit of its stroke, causes the lid to vibrate. When the lid is closed with the force of the finger tip from its opened position, the resisting force of the spring acts directly on the finger and gives an unpleasant sensation. In any event, the conventional devices do not give the impression of being sophisticated mechanisms.
Many attempts have heretofore been made to develop devices capable of properly moderating the movement of a lid, causing the lid, on release from its closed position, to be opened smoothly yet steadily and slowly and, on return to its closed position, to be closed with a proper positive sensation. Among the various devices developed for the control of lid movement, typical are those making use of mechanical frictional force and those incorporating rods in cylinders filled with oil. The devices of the former type have a constitutional problem in that the smoothness with which the lid movement is slowed or stopped is not sufficient and a disadvantage that their component parts tend to squeak because of friction. In that case of the devices of the latter type, since the linear motion of the piston causes the oil contained within the cylinder to move violently within the cylinder interior, the seal tends to be damaged often to the extent of causing oil leakage. Besides, these devices, as a whole, are apt to occupy large amounts of space. Worse still, these devices comprise numerous parts and, therefore, inevitably require much time and labor at the time of their assembly and prove expensive in many respect.
Other devices aimed at moderating lid movement by converting the movement into a rotation around an axis and damping the force of this rotation by means of an oil disposed around the axis of rotation have been also developed. In principle, the devices of this type are capable of producing a moderating force with a highly pleasing sensation. All the efforts made to minimize the number of component parts, however, have been unsuccessful in the devices of this type so far developed. Most of these devices require at least three or four component parts, which are difficult to shape and assemble.